Role of peridural fibrosis in the failed back: a review.

Failed back surgery syndrome (FBSS) is the presence of persistent, disabling pain in the hip, thigh, leg, or lower back of a patient who has undergone a laminectomy or discectomy. Some degree of FBSS is found in approximately 15% of such patients. There may be a direct relationship between the extent of pathology found during the initial surgical procedure and the probability that FBSS will develop. Although FBSS is usually due to improper diagnosis and surgery, another important cause is peridural fibrosis. Part of the answer may have to do with neuromechanics. In a healthy person, pain associated with dural and nerve root movement does not typically occur when performing activities of daily living. In contrast, in a person with peridural scarring, the dura and nerve roots are bound by fibrosis, and putting traction on the nerve roots and dura by back and limb movement produces pain. This pain is aggravated by the presence of inflammation at the surgical site. Research has shown that disc herniation activates the arachidonic acid cascade, resulting in the production of prostaglandins E1 and E2 and leukotriene B, substances that contribute to an inflammatory process that persists after discectomy. In an attempt to inhibit peridural fibrosis, methylprednisolone, polyethylene films, and fat grafts have been applied to the dura after discectomy. These experimental treatments have had limited success. Development of a therapy that reliably prevents peridural adhesive fibrosis will reduce the incidence of FBSS.